Combination storm louver and automatic back-draft damper



Oct. 1, 1968 A. w. NELSON COMBINATION STORM LOUVER AND AUTOMATICBACK-DRAFT DAMPER Filed Oct. 21, 1965 United States Patent 3,403,616COMBINATION STORM LOUVER AND AUTO- MATIC BACK-DRAFT DAMPER Arthur W.Nelson, 343 S. Dearborn St.,

Chicago, Ill. 60604 Filed Oct. 21, 1965, Ser. No. 499,214 3 Claims. (Cl.98-119) ABSTRACT OF THE DISCLOSURE Pivoted damper blades are combinedwith stationary louver blades to serve as automatic closures againsttheentry of rain, even though driven by high winds, into a ventilator. Thedamper blades are mounted, between spaced louvers in suchmanner as toform wind receiving pockets for maximum eflicien-cy in automaticallyclosing the damper blades.

This invention relates to a combination storm louver and automaticback-draft damper for a ventilator or the like and is particularlyconcerned with a combination of fixed louvers and freely pivoted movablelouvers which may be opened by the pressure of air from an airconditioning apparatus or the like but which will automatically closeagainst the entry of rain into the ventilator.

One object of the invention is to provide a plurality of stationarylouver blades sloping downwardly and outwardly relative to a ventilator,and back-draft damper blades freely pivoted along their upper edges inthe spaces between successive louvers.

Another object is to provide each damper blade pivoted adjacent thelouver blade above it and arranged to slope downwardly and outwardlyfrom the pivotal connection whereby gravity tends to close the loweredge of the damper blade against the stationary louver blade below it.

Another object is to provide the arrangement just referred to operableto permit opening of the damper blade by the flow of exhaust air fromthe ventilator, but whenever wind velocity or pressure exceeds theexhaust air velocity or pressure, closure of the back-draft damper bladeis effected so that any rain driven by the wind will be stopped by thedamper blade and drained downwardly and outwardly along that portion ofthe upper surface of the fixed louver blade which lies outwardly of theclosed end of the damper blade.

Still another object is to provide each damper blade with a stop flangealong its lower edge which is parallel to and engaged against the louverblade below it in the closed position of the damper blade to provide aneffective sealing area against the entry of wind-driven rain into theventilator.

A further object is to provide damper blades which have upper and lowerplanar portions arranged with their lower surfaces at obtuse anglesrelative to each other to increase the effectiveness of the closingaction of the damper blade when acted upon by wind pressure.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mycombination storm louver and automatic back-draft damper, whereby theobjects above contemplated are attained, as hereinafter more fully setforth, pointed out in my claims and illustrated in detail on theaccompanying drawing, wherein:

The figure illustrates a vertical cross sectional view through aventilator with my combination storm louver and automatic back-draftdamper construction applied thereto, several modified shapes ofback-draft damper blades being illustrated.

On the accompanying drawing I have used the reference numeral toindicate a ventilator shaft through which air is discharged from an airconditioning appa- 3,403,616 Patented Oct. 1, 1968 Ice ratus or'thelike. At the upper end of the shaft 10 a series of stationary louverblades 12 is provided which may be arranged on all four sides of theshaft 10 for simultaneous discharge from all four sides of the exhaustair, or from two or three sides when wind pressure closes one or two ofthe sides. The louver blades 12 slope downwardly and outwardly from theventilator shaft 10 and are spaced apart as illustrated. Each one isprovided with the usual drip flange 14 along its outer edge.

Below the uppermost louver blades 12 I show substantially fiatback-draft damper blades 16, each having a stop flange 18 along itslower edge substantially fitting against the louver blade below thedamper blade. The upper edge of the damper blade is hinged as indicatedat 20 for free pivotal movement.

At the right side of the figure the damper blade 16 is open due to thedischarge of air from the air conditioning apparatus as indicated byarrows 22. The damper blade 16 and a second damper blade 16 for the farside of the shaft 10 are also shown terminating between end walls 24 forthe 1ouvers'12 on that side of the shaft. The remaining damper bladesfor the far side of the shaft have been omitted.

Whenever wind velocity or pressure exceeds the ex haust air velocity orpressure, however, the damper blade 16 will automatically close as shownat the left side of the figure where the wind direction is indicated byarrows 26. The closed damper blade thereby forms a barrier for the windand particularly for any rain carried by the wind which impinges theouter surface of the damper blade, runs down it and over the stop flange18 and then on to that portion of the louver blade below the damperblade outwardly of the damper blade as indicated by arrows 28. I havefound in actual practice that this arrangement prevents all possibilityof rain being driven in through the combination storm louver andback-draft damper arrangement disclosed, thus eliminating the floodingof air conditioning apparatus, or any space connected with the shaft 10,in a very eflicient manner.

I have found that the damper closing action of the damper blades may beincreased if instead of flat damper blades such as shown at 16, humpedshapes such as shown at 16*, 16 16 and 16 are used. These humped damperblades have upper and lower planar portions 30 and 32, their lower orinner surfaces being at obtuse angles relative to each other. Thedimensions of the planar portions and the angles referred to may vary asillustrated by the four different shapes illustrated. At the right sideof the figure open positions of the damper blades 16, 16 16 16 and 16are illustrated and these open positions may vary with differentrelative pressures between the inside of the stack 10 and the atmosphereoutside the ventilator, and with the encountering of different windvelocities, the damper blade in each case assuming a balanced positionas between the pressures on its opposite surfaces. In some instances,the blades will be wide open such as indicated for the blades 16 16 and16 at the right side of the figure, two of the blades 16 being shown,the upper one partially open and the lower one fully open.

All of the damper blades are preferably provided with the stop flanges18 which may stop against the louver blade below the damper blade oragainst a vertical flange 34 at its upper inner edge as shown for thedamper blades 16 and 16 at the left side of the figure. By having thestop flanges 18 parallel to and against the surfaces they engage, anarea of effective seal against the entrance of driving rain is providedaided by the pressure of the wind against the outer surface of thedamper blade, greater pressure producing more effective sealing actionagainst greater wind-driven rain force.

Actual installations of my combination storm louver and automaticback-draft damper have proven very elfective against the entry of rain.into ventilators even when the rain is driven by high winds. The arrows26 at the upper left corner of the figure illustrate how the Windimpinges the outer surface of the damper blade 16 and is trapped in apocket between the damper blade and the adjacent exposed surfaces of thefixed louvers 12. Similarly, the damper blades 16, 16", 16 and 16 areheld in their closed positions by wind pressure which in the case ofeach ditferent shape and dimensions of planar portions of the back-draftdamper blade varies in effectiveness. The shape and dimensions may,accordingly, be varied to suit different requirements.

From the foregoing specification it is obvious that I have provided asimple arrangement of fixed and movable louver and back-draft damperblades effective to permit substantially free flow of exhaust air from aventilator but prevent the entry of wind and rain on the windward sideor sides of the ventilator.

Some changes may be made in the construction and arrangement of theparts of my combination storm louver and automatic back-draft damperwithout departing from the real spirit and purpose of my invention, andit is my intention to cover by my claims any modified forms of structureor use of mechanical equivalents which may reasonably be included withintheir scope.

I claim as my invention:

1. In a combination storm louver and automatic backdraft damper, aventilator having stationary louver blades sloping downwardly andoutwardly relative to said ventilator, and back-draft damper bladesfreely pivoted along their upper edges in the spaces between successivelouver blades, each of said damper blades being pivoted adjacent 4. athe under side of the louver blade above it and sloping downwardly andoutwardly from the pivot with its lower edge closing against the louverblade below it, the closed position of the damper blade being maintainedby external wind pressure acting in a pocket formed by said upper louverblade and the closed damper blade and acting over substantially theentire area of said damper blade, the lower edge of said damper bladebeing movable toward the louver blade above it as the damper blade isopened by internal exhaust pressure.

2. A combination storm louver and automatic backdraft damper accordingto claim 1 wherein each of said damper blades has a stop flange alongits lower edge which is parallel to and engages flatwise against thelouver blade below it in the closed position of the damper blade toeffect a sealing area against the entry of winddriven rain into saidventilator.

3. A combination storm louver and automatic backdraft damper accordingto claim 1 wherein each of said damper blades has an upper planarportion and a lower planar portion, said planar portions being arrangedat an obtuse angle relative to each other.

References Cited UNITED STATES PATENTS 614,368 11/1898 Cramer 98-741,254,517 1/1918 Lumm 98-119 1,672,291 6/ 1928 Williams 98-74 2,216,42010/ 1940 Rose 98-95 ROBERT A. OLEARY, Primary Examiner.

M. A. ANTONAKAS. Assistant Examiner.

